[Python-Dev] Proper tail recursion

[Michael Chermside]

> > Well, I think I understand Jython well enough to provide the
> > assurance: Jython is (intentionally, and for good reason) designed
> > to utilize the JVM's call stack. Thus Jython cannot support tail
> > call elimination *unless* it is run on a JVM which does tail call
> > elimination.
>
> I originally thought I'd need to use gcc's tail call optimization to
> achieve my aim (since CPython works the same way), but it
> turned out a
> simple loop would suffice.  Unless Jython's implementation is
> radically
> different (i.e. it doesn't pass frame objects to a function
> that evaluates
> them) then it should be able to be implemented similarly.

Like I said, Jython uses the JVM's call stack. So it certainly doesn't
pass frame objects to a function that evaluates them... Jython
stack frames are actual Java stack frames. This is part of why Jython
does such an incredibly good job of integrating tightly with Java --
Java any Jython functions (methods) can call each other freely because
they're practically the same thing.

-- Michael Chermside